brain - AP Psych Brain and Behavior modified Cell types...

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AP Psych: Brain and Behavior modified: July 26, 2001 Cell types that compose the brain 1.Neurons a.These are the basic unit of the nervous system. b.Neurons produce the ability to sense, think, learn, and move. c.1st main function: process, analyze, and store information. d.2nd main function: Neurons can send information over long distances very quickly. e.Neurons are approximately 50% of brain volume f.There are approximately 100 to 200 billion neurons in the human brain and each has 8000 connections. 2.Glia (Latin for glue) a.These cells have a support role for neurons. They maintain structure of neurons, facilitate the functioning of neurons and control the chemical composition of the extracellular environment. b.Glia are 50% of the brain volume. c.Glia are much smaller and more numerous than neurons. Parts of a neuron 1.Dendrites a.Dendrites are the receiving end of the neuron. They generally receive information from other neurons. b.Dendrites process information, like a small computer or transistor. c.The cell membrane of dendrites has a small electrochemical charge. d.Dendrites are branched like a tree. 2.Cell body (AKA soma) a.Like dendrites, the soma is also involved in processing information. b.Each neuron has one cell body. c.The cell body manufactures energy and proteins for the other parts of the neuron. 3.Axon a.The axon is the output mechanism of the neuron. b.The axon can send messages very quickly over long distances. c.Each neuron has only one axon. d.Action potential: a wave or “spike” of electrical excitation that travels down the 4.Synapse (AKA synaptic terminal, terminal buton) a.This is a small gap between the end of an axon and the dendrites of another neuron. b.Neurons communicate information across the synapse by means of neurotransmission c.The synapse is where most drugs act on the nervous system. Neural impulse 1.Neurons have a membrane that maintains a slight electrical charge. 2.The electrical charge is composed of ions like Na + or K + (like NaCl, salt). a.The cell membrane of neurons has a sodium-potassium pump, which pumps out Na+ and pumps in K+. b.Resting potential: An electrical gradient caused by the differences in postive and negative charges on different sides of the membrane. i.Potential: Another term for voltage. c.The resting potential of most neurons is about -70 millivolts. 3.Ions can move across membrane through special holes called ion channels.
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4.Action potential: An electrical wave of voltage that is used to send messages from the cell body to the synaptic terminal. This is a quick increase in voltage followed by an equally fast return to the original voltage. a.Na+ rushes into the cell, creating an upward spike in the voltage. b.K+ then rushes out of the cell, returning the voltage to its original state.
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This note was uploaded on 08/18/2011 for the course PSY 301 taught by Professor Pennebaker during the Spring '07 term at University of Texas.

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brain - AP Psych Brain and Behavior modified Cell types...

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